The present invention relates to an oven ventilation system. By way of example, such a ventilation system is particularly useful for venting an oven in a food preparation vehicle, such as a pizza delivery vehicle wherein the pizza is both cooked and delivered.
In the past, pizza enthusiasts have generally found it necessary to leave their homes or places of work and travel to a pizza restaurant if they wanted a high quality fresh baked pizza. Although other methods of obtaining a pizza, such as purchasing a frozen pizza, cooking a fresh pizza from scratch or ordering pizza for delivery, have been available for some time, these alternatives to visiting a restaurant are not without drawbacks. For example, frozen pizzas tend not to have the same high quality flavor and consistency as fresh pizzas, and of course, it is often inconvenient to bake a pizza from scratch. Further, ordering a pizza for delivery often results in disappointment for the pizza enthusiast. The delivered pizza is often lukewarm and soggy, and it may have lost flavor en route to the consumer.
Although the pizza industry has attempted to provide convenient delivery service to consumers, the problems attendant with traditional delivery systems have limited the market. For example, it has been difficult or impossible to guarantee the quality of delivered pizzas because of the lack of control over the pizzas once they leave the restaurant.
Until recently, the concept of preparing and cooking pizza in a vehicle en route to delivery destination had not been seriously considered, perhaps at least in part because the difficulties presented by ventilating a pizza oven, which typically operates at temperatures of 500.degree. F. and above, discouraged this approach. However, U.S. patent application Ser. No. 599,497 entitled Pizza Preparation and Delivery System and assigned to the assignee of the present invention, discloses a pizza delivery system in which a pizza is prepared and cooked in a moving vehicle en route to its delivery destination.
In the past, pizzas have been cooked in restaurants or in residential dwellings, where ventilation could be provided by a variety of means. But traditional hood systems in a moving vehicle are not suitable for ventilating a pizza oven for a variety of reasons.
One problem is attributed to the space limitations. While traditional oven ventilation systems involve large hoods with large ducts, the ventilation system of a pizza preparation and delivery vehicle must be relatively compact. In particular, the vehicle itself should be as compact as possible in order to conserve energy costs. Nevertheless, space is required for preparing the pizzas, as well as for storing the pizza shells and the pizza topping ingredients. Thus, a compact pizza preparation and delivery vehicle lacks the space otherwise required by the hoods and ductwork associated with traditional oven ventilation systems.
Another problem which is likewise attributable to the space limitations involved with the above type of vehicle is the fact that since the inside of the vehicle is so small, it is necessary that the ventilation system be extremely efficient and completely reliable. That is, due to its small size the inside of the vehicle can overheat in a very short time span if the ventilation system has insufficient capacity or is not operating properly.
Two other problems relate to the energy costs of operating the pizza preparation and delivery vehicle. First, it is naturally desirable for the oven ventilation system to draw as little power as possible from vehicle's available power supply. Accordingly, it is necessary to vent the oven as efficiently as possible. Second, because the air inside the vehicle will often need to be cooled, i.e., by the vehicle's air conditioning system, it would be extremely inefficient to place an extra load on that system by pulling the conditioned air out of the vehicle with the oven ventilating system.
Still another problem relates to the external environment of the pizza preparation and delivery vehicle. Although traditional hoods have exhausting means in the roof or uppermost part of the hood, problems with weather, bridge clearances, wind resistance, as well as aesthetic considerations may in some cases militate against exhausting hood vapors through the top of the vehicle
Many of these same problems are found in traditional oven ventilation systems which are not located in a vehicle. For example, many kitchens have space limitations which prohibit large hoods and ducts and likewise require an efficient heat removal operation. In addition, the cost of cooling air makes it undesirable to vent the cooled air out of the building with the oven ventilation system.